Useful Information
This page contains many pieces of information that will become handy when writing fanon. This information consists of fan calculations, physical properties, and useful links. Terran C-14 Gauss Rifle The C-14 Gauss Rifle is the main terran armament. Despite its name, the C-14 does not appear to be a fully gauss gun, since shell casings are shown in the cinematics. The C-14 fires 8mm spikes at hypersonic velocities. The calculations below show the firepower of the C-14. Before we Start To get the momentum and kinetic energy we need to establish both the velocity and the mass of the spikes. We need to do this because both the kinetic energy and momentum formula requires both variables to be defined. Establishing the velocity is quite simple: The spikes are said to be fired at hypersonic speeds, and hypersonic is anything between mach 5 and 10, or anything between 1,700 m/s and 3,400 m/s. Thus, as a lower limit, the figure 1,700 m/s can be used. But it can, and probably is, higher then so. The mass is going to be harder to establish, but the technical specifications do give us something to work with, namely the diameter of the spikes – which is 8 mm. We also know from various novels that both iron and steel are used as metals for the more common spikes1, which gives us an indication of the density. So, we know the diameter of the spike, but in order to get a volume we also need the length and shape. The most obvious way to go about establishing those variables would be to look at similar modern ammunition. Modern kinetic penetrators are commonly very long compared to their width, this because such a shape helps when it comes to penetration. By comparison, modern normal bullets are actually quite chubby. As examples of modern kinetic penetrators I’ll point out modern SLAP ammunition, modern flechette ammunition and even larger saboted ammunition. All of them are very long compared to their width. As a lower end we’ll be looking at the SLAP ammunition in order to get dimensions. I say lower end because it certainly doesn't look like a ‘spike’ but still conforms to modern standards on how kinetic penetrators should be formed. As a higher end we’ll be looking at the Steyr ACR flechette darts. A long length is also implied in many of the novels, where marines can nail zerg critters to the walls with the spikes2. The only way that could happen is if the spike is long enough to penetrate the wall and stick there, while also being long enough on the outside to actually hold the critter it just penetrated in the air. So, here's a most beautiful paint image (if I do say so myself) of what round shapes we're talking about: Listed in that image is also the various lengths involved. What follows here are the volume and mass calculations based on the dimensions above (using iron density): The Shorter Spike: Volume/Mass Vtot = Vcyl + Vcone Vcyl = PI * r^2 * h Vcyl = PI * 0.004^2 * 0.02256 = 0.000001134 m^3 Vcone = 0.333 * PI * r^2 * h Vcone = 0.333 * PI * 0.004^2 * 0.01272 = 2.129e-7 m^3 Vtot = 0.000001134 m^3 + 3.129e-7 m^3 = 0.000001347 m^3 Mtot = 0.000001347 m^3 * 7874 kg/m^3 = 0.0106 kg = 10.6 g The Longer Spike: Volume/Mass Vtot = Vcyl + Vcone Vcyl = PI * r^2 * h Vcyl = PI * 0.004^2 * 0.05144 = 0.000002586 m^3 Vcone = 0.333 * PI * r^2 * h Vcone = 0.333 * PI * 0.004^2 * 0.02216 = 3.713e-7 m^3 Vtot = 0.000002586 m^3 + 3.713e-7 m^3 = 0.000002957 m^3 Mtot = 0.000002957 m^3 * 7874 kg/m^3 = 0.02329 kg = 23.3 g 'Alright, now that we’ve established both the mass and velocity for the spikes, it’s time for the interesting numbers – namely kinetic energy and momentum: ' The Shorter Spike: Kinetic Energy/Momentum KE = 0.5 * m * v^2 KE = 0.5 * 0.0106 * 1700^2 = 15.317 kJ p = m * v p = 0.0106 * 1700 = 18.02 kg*m/s The Longer Spike: Kinetic Energy/Momentum KE = 0.5 * m * v^2 KE = 0.5 * 0.02329 * 1700^2 = 33.654 kJ p = m * v p = 0.02329 * 1700 = 39.593 kg*m/s By looking at the technical specifications of the C-14 gauss rifle and its ammunition we thus find that it has a kinetic energy between 15 and 34 kilojoules, assuming the absolute minimum muzzle velocity. For comparison, .50 BMG has a kinetic energy between 15 and 20 kilojoules. That means we can assume at least rough parity between the two in terms of kinetic energy.